Currently, a hierarchical virtual private local area network service (HVPLS) is introduced in order to avoid bandwidth waste due to a case that each provider edge device (PE) broadcasts an unknown unicast packet, broadcast packet and multicast packet to all opposite end devices in a virtual private local area network service (VPLS). In the HVPLS, the network is hierarchized, and full connection is formed at each level of the network. Data forward between devices at different levels is not based on a horizontal split principle but can be performed to each other.
A border gateway protocol auto-discovery (BGP-AD) way is a way for implementing HVPLS. In this way, information about a member such as other PE is discovered automatically by an extended BGP update packet, and then labels are distributed according to a label distribution protocol (LDP), so as to establish a pseudo wire (PW) from a local virtual switch instance (VSI) to a remote VSI. In order to implement HVPLS, routing is filtered according to a route target (RT) strategy, a horizontal split group is created, and a PW established in the BGP-AD way (BGP-AD PW for short below) is added into the horizontal split group statically.
However, in the process for implementing HVPLS as described above, filtering the routing according to the RT strategy, creating the horizontal split group and statically adding the BGP-AD PW into the horizontal split group cause a complex configuration process and a high cost.